farmers seem less able to organize than plantation laborers. Similarly, factory workers are readily organizable, and students in colleges and universities are more easily organized than young people who are not in educational institutions. Institutions which bring large numbers of people together have clearly created one important condition for the creation of political organizations. But although there may be a threshold of density below which a people do not readily organize politically, can we assume there is another threshold above which people are likely to be violent and aggressive? This hypothesis is stated in a suggestive and much-quoted study by Calhoun. He conducted an experimental inquiry into the effects of high density on the behavior of a domesticated albino strain of the Norway rat. As density was increased, male ruts became more engaged in struggles for status, fighting increased, mortality among infants and females increased, homosexuality among male rats grew, and some even became cannibalistic (42, 43). A difficulty in assessing the social and political consequences of high densities among humans is the need to disentangle the effect of other variables. David Hecr (44, p. 32) points out that the central cities with high densities also tend to have older, more crowded housing than suburbs, that they have a higher proportion of lower socioeconomic groups, Negroes, the foreign-born, and persons living alone, and that central cities often have a higher proportion of newer arrivals than their suburbs. These factors, rather than high density, may account for some of the characteristics of high-density urban centers. In short, as in studies of the impact of density on health, it is difficult to sort out other factors which are often associated with crowding, such as low income, poverty, poor housing, and unemployment.* Heer considers some of the conflicting evidence concerning the social effects of density: the increase in mental illness and loneliness versus the evidence and arguments that primary Lies are more intense and numerous in the inner city than they are in the suburbs."'" Hcer concludes by noting that although the social effects of di (Terences in population density are of great significance, they have not been adequately studied, a point that can be made as well with regard to the political effects of population density. Whether or not the incidence of pathological behavior among humans is higher in densely populated regions than in dispersed areas is an issue on which the empirical evidence is quite unclear, but certainly one of the most universally believed social theories is the notion that those who live in rural areas and small towns are more virtuous, trustworthy, less violent, and more reasonable than those who are born and raised in high-density urban centers, liven among urban dwellers in the United States, there is a popular belief in *See John Cusscl, "Health Consequences of Population Density and Crowding," in this volume. 1'See the studies by William Footc Whytc, Michael Young, Peter Wilmott, and Louis Worth died hv Heer (44, p. 33).